Trivia / The Revenge of Shinobi

• Dummied Out: A prototype for the game contains a cartoony bonus level based on the Mandara boss fight from the original Shinobi arcade game and a bad ending where Joe dies instead of Naoko. Unfortunately, little of the bonus level was actually coded in before it got dropped due to ROM space concerns, and the bad ending has no known context.
• What Could Have Been: Hidden in a prototype for The Revenge of Shinobi are a bonus level based on a boss fight from the original game with Ultraman parodies as enemies and an alternate bad ending in which Joe dies and Naoko survives, speculated to be achievable by using Mijin to destroy the final boss.